Users of large linked collections of documents, for instance as found on the World Wide Web ("the Web"), are motivated to improve the rate at which they gain information needed to accomplish their goals. Hypertext structures such as those found on the Web primarily afford information seeking by the sluggish process of browsing from one document to another along hypertext links. This sluggishness can be partly attributed to three sources of inefficiency in the basic process. First, basic hypertext browsing entails slow sequential search by a user through a document collection. Second, important information about the kinds of documents and content contained in the total collection cannot be immediately and simultaneously obtained by the user in order to assess the global nature of the collection or to aid in decisions about what documents to pursue. Third, the order of encounter with documents in basic browsing is not optimized to satisfy users' information needs. In addition to exacerbating difficulties in simple information seeking, these problems may also be found in the production and maintenance of large hypertext collections.
Making sense of very large collections of linked documents and foraging for information in such environments is difficult without specialized aids. As noted above, collections of linked documents are often connected together using hypertext links. The basic structure of linked hypertext is designed to promote the process of browsing from one document to another along hypertext links, which is unfortunately very slow and inefficient when hypertext collections become very large and heterogeneous. Two sorts of aids have evolved in such situations. The first are structures or tools that abstract and cluster information in some form of classification system. Examples of such would be library card catalogs and the Yahoo!.RTM. Web site (URL: www.yahoo.com).
The second type of systems are those that attempt to predict the information relevant to a user's needs and to order the presentation of information accordingly. Examples would include search engines such as those found on the Yahoo Web site, Lycos (URL: www.lycos.com), InfoSeek (URL: www.infoseek.com), Excite (URL: www.excite.com) and Alta Vista (URL: www.altavista.com). In each of these systems a user's search request (i.e. information need), typically in the form of words and phrases, is processed and ordered lists of documents or information that are predicted to be relevant to the user's search request are presented.
The presentation of search results from Yahoo, Excite, Lycos and InfoSeek is by some classification, e.g. by the web site containing the information. However, Excite and Lycos permit alternate specifications for ranking and ordering documents. Generally, these tools "order and rank" the search based on their similarity to the user's topical query, which may include frequency of the terms of the search within the documents, where the term occurred (e.g. in title or body of document) or the proximity of the search terms to each other.
However, the aforementioned techniques for presenting the search results may not be optimal for many situations. For example, it may be desirable to order search results based on the documents frequency of access or based on a historical context of interest. The present invention addresses such a need.